This invention relates to carton blank folding and gluing devices, and more particularly to a carton blank folding and gluing device in which only the attachments required for folding and gluing a carton blank are automatically moved to their predetermined positions according to the type and size of the carton.
In a conventional carton blank folding and gluing device (hereinafter referred to as "a sack machine" when applicable), a carton blank is conveyed while being clamped by a suitable device. The portions, which are not clamped, are subjected to the steps of prefolding, prefolding restoring, final folding and gluing which are carried out along creases or dashed creases with attachments such as spiral folding plates, hooks, retaining belts, retaining bars and glue applying wheels (hereinafter referred to as "gluing wheels" when applicable).
With such a conventional sack machine, whenever the type or size of carton blank to be processed is changed, the attachments thereof are manually set at the positions which has been predetermined for the particular carton blank. The number of attachments whose positions should be controlled is quite large, and it is rather difficult even for a skilled operator to set all of the attachments at the correct positions. This also takes a long period of time and necessitates several trial runs. Thus, with the conventional sack machine, in the case where carton blanks of many different types are folded and glued or carton blanks which are the same in type but different in size are folded and glued, the preparation time occupies a large proportional part of the overall period of time required for the operation of the machine. Thus, the conventional sack machine is low in efficiency.